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Joined: Jan 2005
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Cat Servant
Member
Well, I'll give you points for being observant and thorough!

I think ... (siren sounds, and a robot voice warns 'Danger! Will Robinson! Danger!) ... the ignorance and confusion on the hood issue is quite deliberate.

Look at who sells the systems: the same folks who do sprinkler systems. In both instances, the manufacturers have done their utmost to force customers to use not only their complete systems, but also their design services. They went so far as to 'obsolete' a perfectly fine extinguishing agent in favor of a new one that, amazingly, requires a new system be installed.

These protected sales arrangements make it easy to pass off details of your system as 'code requirements,' when such is not the case. Far too often, the 'expertise' of the installer is limited to just one brand and model of equipment.

I have something of a unique insight into this topic; my first 'real' job was testing various fire and alarm related products for a testing lab. As such, I read an awful lot of the standards, test procedures, and understand the way the system works. There have been a few times where I've had to point out to various 'experts' that the very data and materials they're misunderstanding originated with .... ME! Or, at least, I was there when the data was generated.

On the electrical forums, we may fuss and cuss over code issues- but the other codes seem to get a free pass. I'm really disappointed at some of the ignorance I've seen among "experts."

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Joined: Oct 2000
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Broom Pusher and
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It would be great to get a copy of NFPA 96! Is there a PDF Download available from the folks on Batterymarch Park?

Back in "the day" circa 1980's - late 1990's; when I used to actually work...,
the Ventilation sub assembly to be shut down / not shut down on detection of Combustion were - at best, decided by some sort of Daily Lottery; possibly per the roll of Dice...

Conflicting requests / specifications between the MEP Teams -vs- the Officials of a given Agency, resulted in tremendous ExcedrinŽ Headaches for all involved.

For Hoods, sometimes the MUA was shut down and the EF stayed on; other times the EF was shut down and the MUA stayed on.
Sometimes both MUA and EF were shut down, and other times both stayed on!
There were a few occasions where no one actually cared what the shut down sequence was!
Still get woozy thinking about those installs!

Per the Electrical Designs & Engineering of Refrigeration related Systems; where Flammable, Toxic or Highly Toxic Refrigerants (i.e.: NH3 {Ammonia Systems}) are involved, I have a 10 Page document which Specifies the basic requirements and regulations per the CFC (California Fire Code - CCR Title 24, Part 9).
Very minimal Data, but its something.

A somewhat related issue existed back then - and has reared its ugly head again recently... Placement of Duct Smoke Detectors in Plenums for HVAC Package Units.

Conflicts pertaining to which Duct should be monitored - Supply Air or Return Air - spawned some rather interesting Designs & Addenda!

There have been many instances, where only the Supply Air Plenums were specified to be monitored.
Even after initiating RFI Blitzkriegs, the "Commands" were to monitor Supply Air Plenums only.

(BTW, the Duct Smokes were installed no farther than 60" from the Package Unit, and - of course - had the typical 1/2" EMT Monitoring Tube running through the center of the Duct, perpendicular to the Air flow)

It makes sense (at least to me) to monitor the Return Air Plenums for Combustion (Smoke), not the Supply Air Plenums themselves.
Economizers and OA Fans bring Unconditioned Outside Air in to the Package Unit / Supply Air.
The minimum PPM required to trigger an Alarm Status will be offset by the "Thinned Out Smoke" in the Supply Plenums.

Having both monitored makes sense too. This covers both Supply and Return Air and also monitors the Package Unit for catastrophic failure.

Open for comments.

-- Scott (EE)


Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!
Joined: Mar 2004
Posts: 814
B
BigB Offline OP
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Thanks you guys! Now I can walk in there knowing what I'm talking about. smile

Joined: Jan 2005
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Cat Servant
Member
Yes, you can purchase NFPA 96 from ... guess who? ... the NFPA and download it. The download IS limited, so I suggest the first thing you do is print yourself a copy. (I think it's about 30 pages long- and the parts we are concerned with are on only one or two of those pages).

The price, if I recall correctly, was about $30.


Joined: Apr 2002
Posts: 7,381
Likes: 7
Member
Scott:
I agree that monitoring both would be ideal. That said, I'm happy that I (Electrical AHJ) do not have to get into this. It's the Fire Subcode AHJs responsibility.

As to the kitchen hoods, I stand on what I posted above. Another interesting job in plan review is a prototype lith ion battery (or something similar/newer) with a few chemical hoods and supression. That has to wait until I get back from a vacation next week! (Along with a lot of others) Going to Arizona & Vegas!!


John
Joined: Aug 2007
Posts: 853
L
Member
NFPA 96, in regards to Kitchen systems 10.2.6 refers you to NFPA 17A wet chemical systems.

17A states that exhaust fans and dampers need not shut down, as the systems have been tested for zero and high velocity flow conditions.

I can not find MAU shut down in 17A. the closest would be "all fuel sources.." must shut down.

In 96- 8.3.2 it shall shut down on activation of system.

I would see (NFPA 96) chap 8 and 10 as 2 independent directives.
chap-8 says to shut down MUA.
chap 10- refers us to NFPA 17A and MFGRS instructions.

Last edited by leland; 04/14/12 03:56 AM.
Joined: Aug 2007
Posts: 853
L
Member
Originally Posted by renosteinke
Well, I'll give you points for being observant and thorough!

I think ... (siren sounds, and a robot voice warns 'Danger! Will Robinson! Danger!) ... the ignorance and confusion on the hood issue is quite deliberate.

[color:#FF0000]#3) Look at who sells the systems: the same folks who do sprinkler systems.[/color] [color:#FF0000]#1)In both instances, the manufacturers have done their utmost to force customers to use not only their complete systems, but also their design services. [color:#FF0000]#1A) They went so far as to 'obsolete' a perfectly fine extinguishing agent in favor of a new one that, amazingly, requires a new system be installed.[/color][/color]

[color:#FF0000]#2) These protected sales arrangements make it easy to pass off details of your system as 'code requirements,' when such is not the case. Far too often, the 'expertise' of the installer is limited to just one brand and model of equipment.[/color]

[color:#FF0000] #4)I have something of a unique insight into this topic; my first 'real' job was testing various fire and alarm related products for a testing lab. As such, I read an awful lot of the standards, test procedures, and understand the way the system works. There have been a few times where I've had to point out to various 'experts' that the very data and materials they're misunderstanding originated with ....[/color] ME! Or, at least, I was there when the data was generated.

[color:#FF0000]#5) On the electrical forums, we may fuss and cuss over code issues- but the other codes seem to get a free pass. I'm really disappointed at some of the ignorance I've seen among "experts."
[/color]


#1) The main reason for this change, was the change in the cooking process.

The industry has changed from animal fat to vegetable oil.
The appliances have also changed.
Due this fact of ingredient/product change, changes needed to be made.

And they were. For the better.

vegetable oil cooks at a much higher temperature, having a greater high auto-ignition potential, and the newer appliances respond to that,. IE: run hotter.

Therefore the change in the chemical was needed.
This was instituted thru testing and real life issues.

Remember the 'Old days'? When CO2 systems were covering the kitchen hoods? Essentially useless.

Back to the "entire system upgrade', this is needed again due the new chemical.
New flow rates and angles of nozzles are important.

This agent works as a foam- covers and smothers.
looks like a moraine covering, and is easily cleaned up with water.

Additionally, we are trained, certified, tested by the State fire Marshall, and re-certified every two(2) years.Distributors of most major suppression MFGRs.

#2) This was instituted by ANSI and UL, No doubt manufactures had some influence, But that is different than the NEC, How?

#3) I find that hard to believe. Sprinkler guys/co. won't touch this stuff.
(personally, I find this comment..... UN-flattering.. Coz I am one. (Did 4 yrs of school and my on job training.(licensed sprinkler fitter) frown )

#4) Nice, I would love to get some more insight on the inner workings of the industry.

#5) Full circle. Funny how life is.

one industry (related) is influenced by manufactures. AFCI ring a bell? Not to mention other electrical code issues. Of course MFGRS have influence.
NFPA- in this end,is only a start. Local AHJ has a big say. To think that MFGRs have no influence, Or the People in the industry are.. Numb. perhaps you have only met the 'Grunts'. All industries have them.
How many 'Licensed' electricians do you know that can only 'plug and switch'? I know many.

PEACE! Thank you for your time. Lee.

Joined: Jan 2005
Posts: 5,445
Likes: 2
Cat Servant
Member
Thanks for the reply.

As for the 'unflattering remark' ... well, I should have aimed my barb a bit better. I was referring to the manufacturers of the equipment, not the installers. I am aware that different unions are at work here...

Higher temps? Auto ignition? CO2?

I'm actually more familiar with the older Halon and dry chemical systems as installed ... CO2 seems to have fallen from favor, though the systems are still made and installed.

I'm all in favor of inventing better products; I disagree with the marketing decision that denies folks the parts needed to maintain an existing system.

OK, with Halon we had the EPA act ... but there was no governmental action behind the switch to the "K" system.

A foam, eh? Interesting. The use of foam is nothing new, and I wonder how the "K" stuff differs from AFFF.

The fire test for "B" type agents (foams, dry chemmical, etc.) involved putting out a flaming pan of heptane (similar in weight to gasoline). That's pretty hot, and the stuff ignites pretty easily. That there is a new rathing, "K", suggests to me that there is a different test. I'd be interested in learning about that test.

Joined: Aug 2007
Posts: 853
L
Member
For some that may not be familiar with The kitchen (NFPA 17A) systems, this is a good overall of basic operation.
It is an Ansul system, but there are several MFGs of this type system. personally I like the Ansul set up and is tech friendly.

http://www.youtube.com/watch?v=pSMbboZnSL0&feature=related

Check out some of the other type systems also. Pretty cool.
I do all of these systems, a little more interesting than just ol' life safety.
This is the stuff that pays my Ex and my mortgage.

Last edited by leland; 04/20/12 09:21 PM. Reason: other utubes
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